In recent years, in order to achieve high breakdown voltage, low loss, and utilization of semiconductor devices under a high temperature environment, silicon carbide (SiC) has begun to be adopted as a material for a semiconductor device. Silicon carbide is a wide band gap semiconductor having a band gap larger than that of silicon, which has been conventionally widely used as a material for semiconductor devices. Hence, by adopting silicon carbide as a material for a semiconductor device, the semiconductor device can have a high breakdown voltage, reduced on-resistance, and the like. Further, the semiconductor device thus adopting silicon carbide as its material has characteristics less deteriorated even under a high temperature environment than those of a semiconductor device adopting silicon as its material, advantageously.
In order to efficiently manufacture such semiconductor devices, it is effective to use a substrate having a large diameter. Accordingly, various studies have been conducted on silicon carbide substrates made of single-crystal silicon carbide and having a diameter of 3 inches or 4 inches as well as methods for manufacturing such silicon carbide substrates. For example, methods for manufacturing such silicon carbide substrates using a sublimation method have been proposed (for example, see U.S. Patent Application Publication No. 2006/0073707 (Patent Literature 1), U.S. Patent Application Publication No. 2007/0209577 (Patent Literature 2), and U.S. Patent Application Publication No. 2006/0075958 (Patent Literature 3)).